You can download previous versions by going to the Creative Cloud app you likely have downloaded and installed, clicking the "Apps" tab, finding Premiere and clicking the little arrow button to the right. You will see an option to display Previous Versions.

You need to tell us specifically which GPU and CPU that you have in your PC. If, for example, you have a 15-year-old PC that's only capable of running 32-bit programs, then you're completely out of luck: All currently downloadable versions of Premiere require 64-bit software and hardware support.

By contrast, if you have a system that's already 64-bit ready but is restricted in its maximum RAM support to only 4GB, then your only choices that are currently available are the original CC 2013 release and the CS6 release. (Versions between the 2014 version and the 2017.1.2 version are no longer available due to a licensing dispute between Adobe and Dolby Laboratories.) Likewise, those are the only two versions that are usable in a system that has only a Tesla-architecture GPU such as a GeForce GTX 200 series since all currently available newer versions require driver version 365 or higher to enable GPU acceleration whereas the Tesla-architecture GPU drivers go no higher than version 342. And if your system's CPU has only a single physical CPU core, forget about it.